The Baths of Antoninus are the largest set of Roman thermae on the African continent and one of the most impressive surviving structures from Roman Carthage. They sit on the seafront just below the Byrsa hill, partly inside a protected archaeological park. The towering granite columns that mark the corners of the main hall still stand and give a sense of the scale of the original building — visitors entered through a series of cold rooms and passed through warm and hot bathing halls before exiting into the open swimming pool that faced the sea.
Only the foundation level remains today — the public bathing floors of the building were on what is now the upper terrace, supported by the labyrinth of brick-vaulted service rooms that visitors actually walk through. Bring water and sun protection; the site is exposed and the marble surfaces get scorching in summer. Entry is included on the multi-site ticket sold for Carthage's main archaeological zones.